Azathioprine

Why Are Azathioprine Tablets Used?

Azathioprine is a disease-modifying anti-rheumatic drug (DMARD) that helps by calming an overactive immune system. It is used in conditions such as rheumatoid arthritis, systemic lupus erythematosus (SLE), uveitis, and certain other autoimmune diseases. It may also be used where steroids alone are not fully effective.

How Do You Take It in Sri Lanka?

Starting dose: 50 mg once daily.
Dose escalation: The dose is increased every 2 weeks depending on your blood reports (full blood count and liver function). The usual escalation is:
- – 50 mg once daily → 75 mg daily → 50 mg twice daily → 75 mg twice daily.
The dose is adjusted carefully by your rheumatologist depending on your response and your blood test results.

A test called TPMT (thiopurine methyltransferase) may be used in some countries to predict who might develop side effects.
In Sri Lanka, TPMT testing is not routinely done because it is very expensive and TPMT deficiency is not commonly found in our ethnic groups.

When Can You Expect Benefits?

Symptoms often begin to improve within 6–8 weeks.
Protection against long-term joint or organ damage develops over several months.

Important Safety and Monitoring

Blood tests:
- Every 2 weeks during dose escalation.
- Once the dose is stable, every 1–3 months.
Why blood tests?
- To check your blood counts (to ensure they do not drop too low).
- To check your liver function.
Common side effects: mild stomach upset, nausea, or diarrhea (taking after food helps).
Less common but serious:
- Low blood counts → infections or easy bruising
- Liver function changes
- Allergic reactions (rash, fever, muscle aches)

If you develop fever, rash, severe mouth ulcers, or unusual bleeding, stop the drug and contact your doctor immediately.

Key Things to Remember

Take exactly as prescribed—do not stop suddenly unless advised.
Blood tests are essential to make sure the medicine is safe and effective.
Improvement may take 6–8 weeks.
Azathioprine may be used with steroids, NSAIDs, or other DMARDs.

Further Reference

Australian Rheumatology Association (ARA) patient leaflet on Azathioprine: